1. Field of the Invention
The present invention relates to a flexible coupling, equipped with a damping device, specifically for a motor vehicle drive.
2. Description of the Related Art
In internal combustion engine drives, flexible couplings equipped with damping devices are utilized to keep torsional vibrations away from the following drive train. The damping capabilities of the flexible coupling, which is normally mounted on the motor flywheel, plays a special role in critical operational conditions.
In a coupling which is described in German patent document no. DE 3 923 749 (U.S. Pat. No. 5,194,045), a so-called floating damping ring, which is not connected positively with either coupling half, is provided in the interior space of the coupling that is filled with the damping medium. The floating damping ring forms at least a first displacement chamber, together with the first coupling half, and at least a second displacement chamber, together with the second coupling half. In this method, the floating damping ring is subjected to the free force-cycle during the relative movement of the two coupling halves, whereby it is twistable to a limited extent relative to each of the two coupling halves. In considering the dead weight of the floating damping ring, as well as the available gap cross sections, it is possible that, with small oscillation amplitudes, only one displacement chamber becomes effective for damping.
On larger oscillation amplitudes, especially at lower oscillation frequency, the second displacement chamber also becomes effective when the limited twisting of the floating damping ring relative to the one coupling half is being utilized and the twisting relative to the other coupling half is still available. The choice of two separate displacement chambers at the location of one floating damping ring offers the advantage that the coupling can react automatically with a damping of the torsional vibration, which is dependent on the energizing oscillation amplitudes. The coupling can also improve quiet running, even during load change processes.
This arrangement has proven itself in practical applications. However, at lower speeds an operational condition may occur in which the floating damping ring does not fulfil the function demanded of it to the required extent. U.S. Pat. No. 5,573,460 describes displacement chambers that are conductively connected. The damping ring is connected rigidly with one of the two coupling halves. It forms several displacement chambers with the other coupling half.